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Thread: Heather and electric propulsion

  1. #36
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    Default

    Howard, please keep us updated. I am planning on an electric auxillary for my current build ( actually rather committed at this point). I am very interested in your results.

  2. #37
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by Howard Rice View Post
    Hi Rob
    I am looking to change because Heathers little diesel was removed and is not with the boat. Her previous owner Marty put real leg work into electric propulsion and seems to have a solution. I however am new at electric propulsion and am looking for input, opinions, ideas, etc.

    as per Marty's plan and advice from an electric propulsion expert:
    I paraphrase:
    "The idea is to use an appropriate sized electric motor, four 12v batteries, a charger, controller, 3:1 or 4:1 Baldor reduction gear, shaft and prop appropriate to the motor and reduction ratio; solar panel(s) and 2000-watt Honda or Yamaha portable generator.

    The basic concept is to obtain a sweet-spot (motor only, no sails) cruising speed for 7-8 hours of running time without firing up the generator, or be able to run “forever” at the same hull speed if using the generator—which would according to calculated figures will stay just ahead of battery drain at the all-day cruising speed. Of course, if I run the boat at a slower speed, or motor-sailed on light-wind days to provide just a little boost to sail-only hull speed, the electric motor could far longer than 7-8 hours before draining the bank of batteries.

    If the generator is fired up as needed I’d stay ahead of any potential battery drain."

    This is the general plan Marty hatched and his paraphrased words above. Much of the electric propulsion system came with the boat so I am in.

    Thanks, Howard. She really is cool. The plans make her even cooler, being able to see what she’s like under the skin.

    The whole concept sounds grand. We never had as much displacement to play with, nor were we able to entertain having a generator.
    I hope you get her all worked out.

    And share more pictures of your boat.

    Peace,
    Robert
    Last edited by amish rob; 11-16-2018 at 12:05 PM.

  3. #38
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    Default Re: Heather and electric propulsion

    Remember, 746 watts = one hp, and the last time I looked, lead acid and Edison (NiFe) batteries have about 15 watt-hours per pound. Modern batteries have better specific energy.

  4. #39
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    Default Re: Heather and electric propulsion

    If you could turn the 450 lbs. of lead keel into 450 lbs. of battery compartment (with decent hydrodynamic properties) what would help with runtime. I've not looked at the form factor, but many electric car guys are buying used Prius battery packs and replacing just the dead cells, and keeping the rest. The pics I've seen seem to be pretty flat, and prices are in the sub-$200 range. Charging tech required, but could be no storage lost. Of course, running aground could be catastrophic in many ways.

    If you could combine the functions of generator and easily-mountable outboard motor, you could save a little room/weight, too. Something easy to deploy (because permanent mount would be an eyesore) but that drives either standard prop or efficient (inverter?) generator head.

    All that said, custom is often the enemy of reliable... So perhaps my contribution is "here's what not to do".

    On edit: And, it's a fantastic looking boat.
    Last edited by Chip Chester; 11-16-2018 at 10:27 AM.

  5. #40
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by Howard Rice View Post
    Hi Rob

    as per Marty's plan and advice from an electric propulsion expert:
    I paraphrase:
    "The idea is to use an appropriate sized electric motor, four 12v batteries, a charger, controller, 3:1 or 4:1 Baldor reduction gear, shaft and prop appropriate to the motor and reduction ratio; solar panel(s) and 2000-watt Honda or Yamaha portable generator.

    The basic concept is to obtain a sweet-spot (motor only, no sails) cruising speed for 7-8 hours of running time without firing up the generator, or be able to run “forever” at the same hull speed if using the generator—which would according to calculated figures will stay just ahead of battery drain at the all-day cruising speed. Of course, if I run the boat at a slower speed, or motor-sailed on light-wind days to provide just a little boost to sail-only hull speed, the electric motor could far longer than 7-8 hours before draining the bank of batteries.

    If the generator is fired up as needed I’d stay ahead of any potential battery drain."
    ....
    Let's analyse this plan a little more detailed.

    To install:
    4 x 12V batteries
    2000W generator
    Solar panels

    To perform:
    7-8h battery time
    Charge batteries while motoring.

    First the batteries. I don't know what type and capacity the expert advised but 12V probably means lead acid chemistry. Total system voltage is actually not important because total energy stays the same, but for best performance I will asume 48V.
    We need a real battery to analyse, so I will select a time honoured product used often for traction, the Trojan T105. This is a 6V, 225Ah, 62lbs. battery. 225Ah is the capacity for a 20h discharge, but we want the 7-8h discharge capacity. 5h is 185Ah and 10h is 207Ah. Let's say our figure is 200Ah. Trojan says to not regularly discharge the battery under 80% or risk damaging the battery. This means our usable capacity is now 160Ah. So now we have 48V x 160Ah = 7680 Wh to feed to the motor during 7-8h. 7680Wh / 8h = 960W that we can feed the motor with. 960W / 48V = 20A on the wires. So our motor needs to be rated 48V/20A continous duty. Depending on the flavour of motor/controller/gear reduction chosen the prop might see 70-90% of this power, meaning 672-864W. The rest heats up the boat.
    Net result is a 1HP propulsion unit, functioning for 8h. Total system weight is as follows: 8x62lbs=496lbs. + motor + transmission + controller + charger + cables + battery trays = at least 550 lbs.
    To this we add a suitcase generator. Specs for the Honda EU2200i say 1800W, 46.5lbs. dry weight, 0.95 USgal tank and a runtime of 3.2h on a tank. The 1800W get cut to 1600W by the charger. 960W go to the motor, so 640W can go into the battery. 7680Wh to replace in a discharged battery, so asuming the batteries could actually take all of the 640W it would take 12h of runtime and 4 gallons of gas. Lead acid batteries don't work that way, but it gives us a ballpark for our weight calculations: 550lbs propulsion unit + 46.5lbs generator + 5 gallons of gas in a can. So this brings us to a best case scenario estimate of 600lbs for the system and it could jump to 700lbs without beeing overweight and overspec. Actual total runtime at 1HP in perfect conditions should come to a little over 24h. What speed can be obtained with 1HP and if the boat can take 600-700lbs without problem is not for me to say.

    No I have not forgot the solar power. By now anyone should be able to see solar is for running the electronic gadgets, not powering the boat.

  6. #41
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    Default Re: Heather and electric propulsion

    So,
    We rationalize putting an electric motor on a boat, knowing it is only good for entering a harbor and motoring slowly for short distance and short time.
    I have a 7hp air cooled Ducati diesel that I bought new in 1978, but hated using because it was so freaking noisy. Been sitting in my storage for 20 years.
    Because of the noise, It was delegated to...wait for it...only entering harbors and motoring slowly and short time.
    But it makes heat (heat is GOOD in the PNW),and electricity,runs 7 hours on a gallon of fuel, and CAN be run hard for a LONG time in an emergency.3 things electric cannot do.
    I have one of those Honda 2000's, It charges dc at only 8 amps. Maybe they have another model that has different circuits for dc charging only?

  7. #42
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    Default Re: Heather and electric propulsion

    Gents and Ladies
    This discussion and suggestions are valuable, all of them. As mentioned I my post I am not an electric savvy sailor. I have a new boat who's previous owner (highly skilled) was going down the electric propulsion path and he like me is not an electric propulsion expert. He was getting good advice from someone who has put his brain on the question.

    I am copying all the back and forth and suggestions here (pro and con) and am sure glad I posted.

    All options are open in my mind including if the fingers point that way a new small diesel, although I intend to fully explore the electric option.

    Heather is in my humble opinion a very special small boat and she is in excellent condition. This said she deserves (as do I) a smart propulsion system and of course this said I am an avowed engineless sailor so......................well see what shakes out. Heather is a slippery shape and is rigged to really sail and then motor if desired. She is not a motor sailor in spite of her looks, she is a unique sailing vessel. She has dusted more than a few purportedly faster boat under sail, well given her length and theoretical speed.

    This is such a great thread, packed full of information and I am appreciative. Always good to learn new aspects of sailing and propulsion.unnamed.jpg
    Heather.jpg
    13576779_10153920904900000_7046816539839919861_o.jpg

  8. #43
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    Default Re: Heather and electric propulsion

    I've offered what little I had to contribute on the subject given that I have never actually installed an electric motor in a boat. At least not one larger than about 8" LOA. But I think it's worth commenting on the idea that Howard is "rationalizing" electric power in the face of overwhelming evidence in favor of installing another diesel engine. I don't think anyone believes that electric power at this stage of development is a practical alternative to fossil fuels for most uses. But the same argument could be made about most of the boats we own and maintain. Certainly Heather herself is not a practical boat. And her very impractical nature is the reason that so many people like her so much (myself included). So if Howard likes the idea of electric power and goes into it with realistic expectations for the result then I think we can remove practicality from the discussion. For myself, I am looking forward to seeing how the conversion comes together. I'm sure I will learn something.

  9. #44
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    Default Re: Heather and electric propulsion

    If you go the hybrid system route and use a generator, you'll need to devise a way to get the genset's exhaust out of the boat. CO is deadly, of course.
    Another generator issue is, "installation." You'd certainly want to secure the genny; tie it down. But, at some point if the powers ( USCG, insurance, surveyor, etc) decide it is a, " permanent," installation, then it will be subject to much more stringent rules with which a portable genny is not likely to comply. Ignition-protection, for instance.

    Good luck with what ever you decide. I will be watching with interest.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  10. #45
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by cstevens View Post
    I've offered what little I had to contribute on the subject given that I have never actually installed an electric motor in a boat. At least not one larger than about 8" LOA. But I think it's worth commenting on the idea that Howard is "rationalizing" electric power in the face of overwhelming evidence in favor of installing another diesel engine. I don't think anyone believes that electric power at this stage of development is a practical alternative to fossil fuels for most uses. But the same argument could be made about most of the boats we own and maintain. Certainly Heather herself is not a practical boat. And her very impractical nature is the reason that so many people like her so much (myself included). So if Howard likes the idea of electric power and goes into it with realistic expectations for the result then I think we can remove practicality from the discussion. For myself, I am looking forward to seeing how the conversion comes together. I'm sure I will learn something.
    Electric power does have a certain appeal and it is an interesting idea/discussion but even impractical boats need to be practical enough to get used. Otherwise, what's the point?
    -Jim

    Sucker for a pretty face.
    1934 27' Blanchard Cuiser ~ Amazon, Ex. Emalu
    19'6" Caledonia Yawl ~ Sparrow

    Getting into trouble one board at a time.

  11. #46
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by wizbang 13 View Post

    I have one of those Honda 2000's, It charges dc at only 8 amps. Maybe they have another model that has different circuits for dc charging only?
    I think the usual approach is to use the AC full output to drive a separate, smart, battery charger.

  12. #47
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by cstevens View Post
    I've offered what little I had to contribute on the subject given that I have never actually installed an electric motor in a boat. At least not one larger than about 8" LOA. But I think it's worth commenting on the idea that Howard is "rationalizing" electric power in the face of overwhelming evidence in favor of installing another diesel engine. I don't think anyone believes that electric power at this stage of development is a practical alternative to fossil fuels for most uses. But the same argument could be made about most of the boats we own and maintain. Certainly Heather herself is not a practical boat. And her very impractical nature is the reason that so many people like her so much (myself included). So if Howard likes the idea of electric power and goes into it with realistic expectations for the result then I think we can remove practicality from the discussion. For myself, I am looking forward to seeing how the conversion comes together. I'm sure I will learn something.
    I disagree with the thinking that Heather is "impractical". She is unconventional, but the combination of features is good, she sails well, will stand upright when grounded on a falling tide for maintenance or in a sheltered corner, she has a nice cockpit, a sheltered helm if desired, can sleep three, has a little galley and as many mod cons as needed. She can be trailered on a flat bed trailer, is of a size thats easily managed. I don't see anything impractical.
    In fact, considering that Howard spent 45 days and nights on board his SCAMP, Heather is practically a luxury liner.
    I'm looking forward to "meeting" her.

    John Welsford
    An expert is but a beginner with experience.

  13. #48
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    Default Re: Heather and electric propulsion

    PS First..........I penned below before seeing John's comments above.

    Thanks Chris.
    Actually not rationalizing (I hope;-), mind totally open given this one caveat. The boat comes with some of the electric propulsion system components and no diesel....................so I am learning and for now leaning.

    On the other mention. I happen to see Heather as a highly practical boat (for me at least) from many perspectives given a second caveat, I prefer sailing small boats most of the time. I have never owned a boat anything like this one but I understand what she is and what she is capable of. This one works for me on many cylinders (no pun intended). Heather for my taste is something very special and for sure not a boat for most as I reckon some, likely many think her oddball ugly and yes impractical.

    I see a truly unique beauty in a world of cookie cutter boats and a fully found micro yacht. Having been aboard her I can say she is a sight to behold above and below deck. Nothing extra, nothing added on, function is it.
    13558830_10153920914240000_9162174367154381369_o.jpgHeather-2-1.jpg13575896_10153920916180000_109682127051331435_o.jpg
    Last edited by Howard Rice; 11-16-2018 at 01:56 PM.

  14. #49
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    Default Re: Heather and electric propulsion

    To run continuously with genset pushing the batteries might be an issue. I'd expect her to be using around 2000 watts or a little more at flat water cruising speed. With all the losses in the system that would mean a genset output of about twice that to maintain, so a 5000 watt genset would be about right. But thats a big genset, not the sort of thing you'd want to live with in a 16 ft boat.
    So the alternative is to run direct, power the propulsion motor direct from the genset, which would mean about a 3000 watt generator, thats about 4 1/2 hp output, with losses you'd end up with a 3 hp output to the propellor. The Honda EU3000IS is 59 kg, has a 200cc single cylinder gas engine for power and while compact for its kind is still something that would require some thinking to house.
    The next alternative would be to have a decent sized battery bank, and Li batteries have a lot of energy storage for their volume, use those to powered her in and out of marinas, tight anchorages and such, and have a very small genset which could be run for hours when the boat is not under way or when under sail, to recharge.

    Compromises, compromises, the question being which compromise?

    Do appreciate that I'm not an expert on electric or hybrid systems, and I could be completely wrong.

    John Welsford
    An expert is but a beginner with experience.

  15. #50
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    Default Re: Heather and electric propulsion

    Doesn't having to run a genset while sailing or for hours on end to charge the battery bank back up kind of defeat the whole purpose of going to an electric set up to begin with? If you can regularly take advantage of shore power and skip the genset though...
    -Jim

    Sucker for a pretty face.
    1934 27' Blanchard Cuiser ~ Amazon, Ex. Emalu
    19'6" Caledonia Yawl ~ Sparrow

    Getting into trouble one board at a time.

  16. #51
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    Default Re: Heather and electric propulsion

    Aha Mr Welsford Sir
    Since I have offered Heather to you for your cruising pleasure when in the PNW I look forward to collaborating with you on her power plant. Tim Nolan her designer/builder is all in on the hybrid electric approach and had gone as far as to figure the generator when in battery charge mode at anchor could sit atop the tiny aft house chugging almost silently with exhaust wafting away down wind. Marty figured the generator would fit nicely in the port cockpit locker when not in use. Generators sip gas when compared to running an engine.

  17. #52
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by Geftb View Post
    You could get 30 (slow) miles only with the help of a generator. I'm not saying that's a bad thing.
    It all depends on how many / how big your batteries are. Around here I deal with river/ICW cruising and it's nice to be able to go to aux power, sometimes for 30+ miles. For me, electric just isn't an option - I mean, I could do it, with three big 96V lithium banks (charged by dock power or solar through the week, discharged on the weekend) plus a 10kW generator, but... that's quite a bit heavier, more complex, and expensive than the diesel alternative.

    Where electric would make sense to me would be island hopping, particularly in the Caribbean. If you only need to run your motor for 10-20 minutes at a time and then can wait for 2-3 days for a big solar array to recharge the batteries before you use the motor again, it's great - one small battery bank can do it. It would be particularly cool in a catamaran with twin electric driven screws, and I suppose might make sense if one of those is a hybrid that can either provide long term diesel powered drive when needed and even charge up the batteries when needed - but, again, the hybrid is heavy, complicated, and expensive as compared to a pair of good diesels.

  18. #53
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    Default Re: Heather and electric propulsion

    Generators sip gas when compared to running an engine.
    Let's take a look:

    A 1500 W ( 2 hp) Honda generator reportedly burns 1.1 liters per hour. ( Honda's data: http://www.hondapower.net.pk/applicationUsageChart.htm)

    Screen Shot 2018-11-16 at 2.44.38 PM.jpg


    A Honda BF2 2-hp outboard burns 1 liter per hour.

    http://www.hondampe.com.au/docs/mari...sumption-repor /Fuel%20Consumption%20Data%20Sheet%20-%20Honwave%202.4%20-%20BF2.pdf

    Screen Shot 2018-11-16 at 2.47.13 PM.jpg

    Looks like the genny burns a little more fuel. However, we need to know one thing( at least) before we can call either more efficient: How far will the boat go on a given quantity of fuel burned in the engine versus burning that same quantity of fuel in the generator?



    Kevin

    EDIT: typo
    Attached Images Attached Images
    Last edited by Breakaway; 11-16-2018 at 03:00 PM.
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  19. #54
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by Howard Rice View Post
    Aha Mr Welsford Sir
    Since I have offered Heather to you for your cruising pleasure when in the PNW I look forward to collaborating with you on her power plant. Tim Nolan her designer/builder is all in on the hybrid electric approach and had gone as far as to figure the generator when in battery charge mode at anchor could sit atop the tiny aft house chugging almost silently with exhaust wafting away down wind. Marty figured the generator would fit nicely in the port cockpit locker when not in use. Generators sip gas when compared to running an engine.
    Sounds good to me, I'm looking forward to waking up in Mystery Bay one morning, sitting up with a mug of English Breakfast tea and considering what the day might hold.

    Something to add to your store of information, is that traction batteries such as those used in fork trucks, golf carts and in some cases, mobility scooters, are rebuildable. There are outfits around that will replace the below par cells, effectively making them "new" again, at a much lower cost than purchasing new batteries.
    This makes my earlier suggestion of a disused golf cart more workable.

    John Welsford
    An expert is but a beginner with experience.

  20. #55
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by Howard Rice View Post
    ... figure the generator when in battery charge mode at anchor could sit atop the tiny aft house chugging almost silently with exhaust wafting away down wind.
    Oh please no. There was a visiting boat that had a small Honda generator in our harbor and they ran it like that for the days they were here. Truly annoying to everyone nearby. But maybe you'll be off in the hinterlands?
    If I had a dollar for every girl who found me unattractive, eventually they would find me attractive.

  21. #56
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    Default Re: Heather and electric propulsion

    Howard and John, I meant no disrespect in calling Heather impractical. Quite the reverse. Perhaps I should say she is "whimsical" rather than "impractical", in that while she is quite obviously practical for someone who enjoys her particular charms, those charms may be under-appreciated by the herd of sailors with less refined tastes. She is a special boat for the rare person who can use and enjoy her as she was intended. Seems like she has found her man though.

  22. #57
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    Default Re: Heather and electric propulsion

    Something to consider is the efficiency of the link between the gas motors crankshaft and the prop. The little BF2 Honda ( I have one, great little motor) has one bevel gear and thats it. Not much loss there. The genset has to turn the generator, transmit the energy generated to a battery, incurring losses, then the current has to be drawn off and batteries are not 100% efficient, then an electric motor, again not 100% efficient, drives the propshaft, presumably through some form of reduction gear, again, not 100% efficient.
    Unless very carefully engineered, the potential for loss of efficiency is considerable.

    John Welsford
    An expert is but a beginner with experience.

  23. #58
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by cstevens View Post
    Howard and John, I meant no disrespect in calling Heather impractical. Quite the reverse. Perhaps I should say she is "whimsical" rather than "impractical", in that while she is quite obviously practical for someone who enjoys her particular charms, those charms may be under-appreciated by the herd of sailors with less refined tastes. She is a special boat for the rare person who can use and enjoy her as she was intended. Seems like she has found her man though.
    If there was a "like" button, I'd press it.

    John Welsford
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  24. #59
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    Default Re: Heather and electric propulsion

    Hey Chris no worries at all and no need to apologize for anything. Never took anything the wrong way. I think you are right, whimsical works. She is a funny little thing isn't she. There is something about her that just spoke form/function to me and obviously to you as well. I am very happy to be her new master and plan to do this just right, whatever the outcome. Glad you like her.

  25. #60
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    Default Re: Heather and electric propulsion

    When considering running a diesel-electric system on the boat, it's all about the power.

    If you need/want to use 20hp of output from your engine, that's ~15kW. If you're going to do this for 6 hours straight, that makes 90kWh. If you have 90kWh in your battery pack, you can do that all from battery, once, but before you do it again you'll need to recharge. If you're recharging from a little Honda suitcase, labeled 2kW peak but really 1.6kW continuous capable, it will take over 56 hours of the suitcase running at full bore to replace the power you used in your 6 hour 20hp cruise - if your electrical power management system is sophisticated enough, you can run the generator while running the 15kW motor and that just means a 50 hour break between 6 hour jaunts. Sounds like you're probably going to want a bigger generator, maybe an 11kW model, if you run that while you're running, the generator can output 66kWh during the cruise and the batteries only need to source 24kWh - then, you can take a 3 hour break and fully recharge the batteries and then run for another 6 hours straight.

    11kW gensets are bigger and heavier than 20hp simple shaft spinning motors, then you add the weight and complexity of the batteries and 15kW motor and all the charge management circuitry, cables, etc. There will be inefficiencies in the system that make things not quite as great as they seem at first on paper, but it can be a workable system, if you put enough money and engineering into it.

    The most attractive concept I've heard about the electric systems is charging from solar. I believe an 8 square foot solar panel costs about $230 and outputs about 100W. Assume you've got 80 square feet somewhere in the sun (I like the solar cockpit cover myself) - now, when the sun is strong, you're generating 1kW, enough to charge that 24kW battery pack in 24 hours. Most places in the world it would take between 3-6 full days to do this. However, once done, that's some real power, enough to run at 20hp engine output for for a bit over 90 minutes. If your diesel engine drinks 2gph while putting out 20hp, that means your measly little $2300 solar panel array is generating the equivalent of 3 gallons of diesel power for you every 3-6 days - not bad, not super amazing, but still not a bad thing at all, especially if you're living frugally at anchor somewhere away from civilization.

    Quote Originally Posted by rbgarr View Post
    Oh please no. There was a visiting boat that had a small Honda generator in our harbor and they ran it like that for the days they were here. Truly annoying to everyone nearby.
    There's an island in the Florida Keys with no power lines run to it. People have built a bunch of full size houses on it, and they run their generators ALL THE TIME, it's awful.

    As generators go, the little suitcase models with eco-throttle (spins down the RPMs when not needed) are really nice, as compared to the elCheapo 5KW open frame models, but as compared to no generator at all, they're still unacceptably loud, to me.
    Last edited by MangoCats; 11-16-2018 at 03:37 PM. Reason: Fix bad math

  26. #61
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    Default Re: Heather and electric propulsion

    By the sounds of it Howard is looking for 5-10-20 min max from his electric engine. The maths changes big time then.
    I look forward to what ensures Howard! Please keep us posted.

    Steve

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    Default Re: Heather and electric propulsion

    There is a young couple doing a sailing vlog on youtube "Sailing Uma" who have electric power in their boat. I suggest you check them out. Dan is an Architect or something, and works and talks intelligently about his technical solutions to problems.
    I think Electric power would not suit a person who uses the engine as a major source of motive power, either to get to an intended destination more quickly or even just getting there. Electric may be the perfect power for the person that uses the engine for short periods. such as entering harbor or berthing, or to provide a little boost to get through a tidal pass.

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    Default Re: Heather and electric propulsion

    Here you have a blog of someone who has done exactly what you want. Inboard motor, 4 batteries, Honda generator, motorsailing. Best part is he is doing it for 10 years now, so he has some real world data.
    http://biankablog.blogspot.com

  29. #64
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by john welsford View Post
    The genset has to turn the generator, transmit the energy generated to a battery, incurring losses, then the current has to be drawn off and batteries are not 100% efficient, then an electric motor, again not 100% efficient, drives the propshaft, presumably through some form of reduction gear, again, not 100% efficient.
    Seems to work okay for locomotives ... but if we're going to get impractical, I'd be looking for a tiny gas turbine to run the generator. Drop most of the battery bank and go turbo-electric.

    Military surplus ?

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    Default Re: Heather and electric propulsion

    Quote Originally Posted by gilberj View Post
    There is a young couple doing a sailing vlog on youtube "Sailing Uma" who have electric power in their boat. I suggest you check them out.
    I saw a video they did with two other electric powered cruising couples and it was pretty to-the-point about what electric power is and is not good for.

    Quote Originally Posted by gilberj View Post
    Electric power would not suit a person who uses the engine as a major source of motive power,
    The video linked earlier in this thread hit that one on the head: Electric power absolutely sucks in the Intracoastal Waterway, and by extension, most up-current river and similar applications... I've tried to juggle system components to make it work and the only way it does is to go hybrid, which is basically keeping a full fledged diesel engine on-board in addition to the electric system, and not only is that less efficient in the simple driveline analysis, you're also adding hundreds, perhaps thousands, of pounds to your displacement as well.

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    Default Re: Heather and electric propulsion

    In this case we are really talking about 3 to 4 kw...4 - 6 hp...
    If we assume normally 20 minutes or less continuous running, it becomes workable.
    The idea is to sail whenever you can, even being patient in light winds. And wait for wind if there is none. The motor is supplemental.
    I know most sailors these days, consider the engine to be probably 50% or more of their motive force, but a few of us would rather sail.

  32. #67
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by Favorite View Post
    Seems to work okay for locomotives ... but if we're going to get impractical, I'd be looking for a tiny gas turbine to run the generator. Drop most of the battery bank and go turbo-electric.

    Military surplus ?
    Locos are a special case, they need immense torque at very low speeds, which involves a complex transmission, plus weight is, if anything an advantage in that it improves traction.
    There are quite a few diesel electric ships, the system is very common among special purpose ships such as tugs and those vessels such as drillships and dive tenders which have to maintain station and do so with multiple vectoring thrusters. I've been on board the Joides Resolution https://joidesresolution.org/ had a good look at her propulsion system. That was an interesting visit, you might look her up.

    Bear in mind that Howard has quite recently spent 45 days on board, in very challenging territory, a boat with sails and oars only. I don't think that he'd be using the electric drive very much at all. We're not talking about motoring non stop from Port Townsend to the San Juans. More like manoeuvring in Marinas, occasionally getting off anchor in a tight spot, or motoring into MatsMats bay. ( I've been in there, and no you wouldn't normally sail in or out of there).

    As Howard says, Heather is mine to use should I be able to make it back to the area, and I'm hoping to. I don't think that I'd have her under power much, and even with a flat battery at 16 ft she'd be easy to move with a sweep oar.

    John Welsford
    Last edited by john welsford; 11-17-2018 at 03:02 AM.
    An expert is but a beginner with experience.

  33. #68
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    Default Re: Heather and electric propulsion

    This would do the job nicely but alas, $25,000

    https://newenergyandfuel.com/http:/n...in-a-suitcase/

    And some interesting figures

    http://www.bioturbine.org/Publicatio...01-HILTECH.pdf

    It seems possible that one day this might be a nifty way to power a boat but not in time for Heather's project

    edit: the one they show on this page is actually too small ! but they have another that's one size up. Seems like it would need sound damping but at ten pounds, there should be room

    http://azmark.aero/eproducts.html

    and the IHI one is now $9,000 apiece.

    Dunno but this looks a lot more interesting (long range, probaly way too expensive for this project) than 48,000 lbs of batteries in an electric boat.
    Last edited by Favorite; 11-17-2018 at 02:51 AM.

  34. #69
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    Default Re: Heather and electric propulsion

    Quote Originally Posted by gilberj View Post
    In this case we are really talking about 3 to 4 kw...4 - 6 hp...
    If we assume normally 20 minutes or less continuous running, it becomes workable.
    The idea is to sail whenever you can, even being patient in light winds. And wait for wind if there is none. The motor is supplemental.
    I know most sailors these days, consider the engine to be probably 50% or more of their motive force, but a few of us would rather sail.
    If those are the needs, 4-6hp for 20 minutes or less, then electric is absolutely ready for the job. That's just 1.3kWh, or about 100Ah out of a 12V battery, most people are already carrying around that much lead-acid capacity for other uses, and even a relatively modest/common 200W solar charging system can pump that up in a sunny day or two. Wind generators also can put out that amount of current in a few hours of good wind, when sunshine is at a premium.

    When I day-sail, that fits our use case, and the only reason the 6hp motor runs for 20 minutes is because it has to be pull-started, most of its run time is actually at idle. With push-a-button instant availability I might use more like 5-10 minutes of usually 50% throttle or less.

    Where it falls apart around here is the intracoastal waterway - long (10+ mile) narrow passages with variable winds swirling between obstructions close on both sides - currents that are sometimes/places hard to predict, and then the rare inlet - most of which can turn very nasty with high waves and strong currents, even though it's a nice day just outside. You can plan your inlet passages around the tides, but if wind is also blocking you from exiting, or worse from getting back inside, having competent auxiliary power makes all the difference.

  35. #70
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    Default Re: Heather and electric propulsion

    Re: Turbines

    Quote Originally Posted by Favorite View Post
    This would do the job nicely but alas, $25,000

    https://newenergyandfuel.com/http:/n...in-a-suitcase/
    I looked into the idea of sourcing a "surplus" 400Hz turbine APU genset from an old plane for use in a land vehicle. It would have worked, and maybe come in below the $25K mark, but the major drawbacks would have been outrageous noise levels, and overall fuel economy much lower than normal direct drive piston engines. Guesstimate numbers were running in the range of 4 mpg of kerosene.

    One funny side benefit of the turbine: high pressure bleed air can be fed through a small heat exchanger to dump off most of the heat of compression (in a cruiser this could become a hot water source), then when that air is decompressed it is super-cold. Not sure if you'd want to breathe it directly, but you could at least feed that cold air through another air-air heat exchanger for more cabin air-conditioning than you'd ever need.

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